Neusticosaurus (meaning "swimming reptile" or "swimming lizard") is a genus of very small nothosauroid marine reptiles. Fossil remains have been found in Germany and France. It is similar in size to Keichousaurus. Fossil remains, around 24 to 30 centimetres long, may or may not represent adult individuals. If such fossils belong to adults, Neusticosaurus would be the smallest nothosaur discovered.